Role of equatorially asymmetric sea surface temperature anomalies in the Indian Ocean in the Asian summer monsoon and El Niño-Southern Oscillation coupling

Ryuichi Kawamura, Tomonori Matsuura, Satoshi Iizuka

Research output: Contribution to journalArticle

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Abstract

Using an ocean general circulation model forced by daily mean wind stresses and heat fluxes derived from the bulk formulation with the National Centers for Environmental Protection/National Center for Atmospheric Research reanalysis, we examined possible roles of the tropical Indian Ocean in the Asian summer monsoon and El Niño-Southern Oscillation (ENSO) coupling. A dominant precursory signal of anomalous monsoon circulation relevant to ENSO is the presence of latitudinally asymmetric anomalies of tropical convection and sea surface temperature (SST) near the equator in the preceding spring. The model results show that the equatorial asymmetry of surface latent heat flux plays a vital role in generating the equatorially asymmetric SST in the preceding spring, which implies that a positive wind-evaporation-SST (WES) feedback proposed by Xie and Philander [1994] is crucially responsible for generation and maintenance of those equatorial asymmetries. The westward extension of anomalous convection from the vicinity of the Philippines into the northern Indian Ocean from the preceding winter to spring, which has a signal of ENSO, can be viewed as a developing process of WES. Persistence of the WES feedback regime affects land surface hydrologic processes in the Asian continent through a Rossby wave response to anomalous convective heating. It is anticipated that the WES mode in the tropical Indian Ocean serves as a bridge between the ENSO prevailing in the preceding winter and the anomalous summer monsoon.

Original languageEnglish
Article number2000JD900610
Pages (from-to)4681-4693
Number of pages13
JournalJournal of Geophysical Research Atmospheres
Volume106
Issue numberD5
DOIs
Publication statusPublished - Mar 16 2001

Fingerprint

Southern Oscillation
monsoons
Indian Ocean
sea surface temperature
temperature anomaly
surface temperature
summer
oscillation
monsoon
evaporation
anomalies
Evaporation
heat
winter
Heat flux
heat flux
convection
Temperature
Philander
asymmetry

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Role of equatorially asymmetric sea surface temperature anomalies in the Indian Ocean in the Asian summer monsoon and El Niño-Southern Oscillation coupling. / Kawamura, Ryuichi; Matsuura, Tomonori; Iizuka, Satoshi.

In: Journal of Geophysical Research Atmospheres, Vol. 106, No. D5, 2000JD900610, 16.03.2001, p. 4681-4693.

Research output: Contribution to journalArticle

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